Drilling apparatus

Abstract

A drilling apparatus including a hydraulically powered hammer having a piston to impact a drill bit; a shuttle valve to control reciprocation of the piston; and an accumulator for hydraulic fluid; at least one drill rod having a first connection valve for connection of the drill rod to the connection valve of the hammer; and a second connection valve for connection of the drill rod to the first connection valve of a like drill rod or to a rotation device. The piston and shuttle valve are positioned substantially in-line to the axis of movement of the hammer. The accumulator is positioned proximate to the shuttle valve; and the first connection valve, and second connection valve having at least one poppet valve positioned proximate to a corresponding valve seat.

What I claim is: 
     
       1. A drilling apparatus comprising:
 a hydraulically powered hammer comprising:
 a piston to impact a drill bit; 
 a shuttle valve to control reciprocation of the piston; 
 an accumulator for hydraulic fluid; 
 
 at least one drill rod comprising:
 a first connection valve for connection of the drill rod to a connection valve of the hammer; and 
 a second connection valve for connection of the drill rod to the first connection valve of a like drill rod or to a rotation device, 
 
 wherein 
 the piston and shuttle valve are positioned substantially in-line to the axis of movement of the hammer; 
 the accumulator is positioned proximate to the shuttle valve; and 
 the first connection valve and second connection valve comprise at least one poppet valve positioned proximate to a corresponding valve seat in a hydraulic fluid return line, wherein the at least one poppet valve is biased onto said corresponding valve seat to prevent reverse flow of return hydraulic fluid through the first and second connection valves while allowing for forward flow of return hydraulic fluid through the first and second connection valves. 
 
     
     
       2. The drilling apparatus as claimed in  claim 1 , wherein the drill bit, piston, shuttle valve, accumulator and connection valves are connected substantially in-line to one another. 
     
     
       3. The drilling apparatus as claimed in  claim 1 , wherein the drill bit, piston, shuttle valve, accumulator and connection valves are modular units connected to one another via locating apertures and locking pins. 
     
     
       4. The drilling apparatus as claimed in  claim 1 , wherein the first connection valve and second connection valve are individually replaceable. 
     
     
       5. The drilling apparatus as claimed in  claim 1 , wherein second connection valve comprises an inner connection valve seal and an outer connection valve seal respectively which are configured to prevent internal leakage of hydraulic fluid from a pressure line and a return line, respectively. 
     
     
       6. The drilling apparatus as claimed in  claim 5 , wherein the first connection valve and second connection valve are configured so that, during connection, axial movement of the first connection valve on one drill rod or on the rotation device relative to the second connection valve on another drill rod or the connection valve of the hammer is no more than 50% of the drill rod diameter. 
     
     
       7. The drilling apparatus as claimed in  claim 5  wherein the second connection valve is configured so that, during connection, axial movement of the inner connection valve seal and the outer connection valve seal over the receiving component(s) of the first connection valve of a joined drill rod or rotation device is no more than 20% of the drill rod diameter. 
     
     
       8. The drilling apparatus as claimed in  claim 1 , wherein the drill rod also comprises:
 a pressure line for supply of pressurized hydraulic fluid from an external reservoir to the shuttle valve; 
 a return line to supply return hydraulic fluid from the shuttle valve back to the external reservoir; and 
 a flushing line for supply of pressurized flushing medium to the drill bit. 
 
     
     
       9. The drilling apparatus as claimed in  claim 8 , wherein the return line is an annulus arranged around the pressure line. 
     
     
       10. The drilling apparatus as claimed in  claim 8 , wherein the flushing line is an annulus arranged around the return line. 
     
     
       11. The drilling apparatus as claimed in  claim 8 , wherein the pressure line and return line are individually free floating within each drill rod. 
     
     
       12. The drilling apparatus as claimed in  claim 8 , wherein the pressure line and return line are individually replaceable within each drill rod. 
     
     
       13. The drilling apparatus as claimed in  claim 8 , wherein the flushing medium is air. 
     
     
       14. The drilling apparatus as claimed in  claim 1 , wherein the hammer also comprises an external housing which is adapted to be reversibly fitted to the hammer, such that either end of the housing is connectable to the hammer. 
     
     
       15. A method of using a drilling apparatus, said method comprising the steps:
 assembling a hydraulically powered hammer from modular units, the modular units comprising:
 a drill bit; 
 a piston; 
 a shuttle valve to control reciprocation of the piston; 
 an accumulator; 
 a first connection valve comprising at least one poppet positioned proximate to a corresponding valve seat, for connection of the drill rod to a connection valve of the hammer; and 
 a second connection valve comprising at least one poppet positioned proximate to a corresponding valve seat, for connection of the hammer to the first connection valve of a like drill rod or to a rotation device 
 connecting at least one drill rod to the second connection valve; and 
 connecting a rotation device to the second connection valve of each drill rod, said rotation device imparting rotational movement to the at least one drill rod and hammer; 
 wherein the first connection valve and second connection valve are configured to prevent reverse flow of return hydraulic fluid. 
 
 
     
     
       16. The method of using a drilling apparatus as claimed in  claim 15 , wherein the method also comprises the step:
 connecting the apparatus to a hydraulic feed system adapted to move the apparatus linearly along its line of axis.